In hospitals, it is common to administer fluid and medicaments to patients via the parenteral, or intravenous (IV) route. The vast majority of hospitalized patients and all patients undergoing surgery have an IV catheter placed for delivering medicaments such as antibiotics, emergency resuscitation drugs, for inducing and maintaining anesthesia, and for the infusion of fluid volume and blood products
Two broad functional modes define IV systems: continuous infusion and bolus dosing. The bolus mode is used for medications that are safe for rapid administration and intended for immediate bioavailability. Bolus mode is typically quickly accessible within any IV system because patients routinely are given a variety of medication boluses in addition to one or more concurrent infusions. The frequency of bolus drug administration may range from zero to dozens per day. Occasionally, multiple boluses are delivered in rapid succession necessitating repeated switching between modes, as occurs in surgery and interventional procedures, in the intensive care unit (ICU), in the management of unstable patients, and in medical and surgical emergencies.